The present invention relates generally to elevator brakes and, in particular, to an apparatus for monitoring elevator brake conditions.
In general, brakes operate to convert motion energy into thermal energy. However, elevator brakes are provided solely as holding brakes although they may be applied before the elevator car comes to rest at a floor and when various electrical protective devices are actuated such as in overload/overspeed conditions. If these brakes are heated by excessive braking actions, their holding action can deteriorate. The elevator controller cannot detect the reduced effectiveness of the elevator brake due to overload conditions which occur between two regular visual inspections. Furthermore, the wear of the brake linings depends very much on the use of the elevator, which can vary between two visual inspections. Worn or even broken brake linings will put the elevator out of action prior to the next periodically scheduled visual inspection.
A drawback of the above described elevator installations is that the safety of the passengers is not guaranteed under all conditions. A further drawback is that additional emergency maintenance operations become necessary which worsen the ratio of elevator operation time to down time.
It is here that the present invention offers a remedy. The present invention solves the drawbacks of the known equipment by monitoring the elevator brake and automatically indicating the functional capability of the elevator brake.